If the king and his entourage came to stay with one of his vassals, would the vassal be expected to foot the bill or would the Crown pay some? What about one lord staying with another?

The king would absolutely not pay the bill. Indeed, half of the point of the king going on royal progress and crashing at his vassals’ houses was to gently bankrupt them so they didn’t have enough cash on hand to rebel against you.

I’m not familiar with sub-infeuded examples of the same process. I’m guessing it depends on the terms of the feudal contract, because some of them could be very specific about the responsibilities of the vassal to provide various services and goods when the liege lord came to visit:

Moreover I acknowledge that, as a recognition of the above fiefs, I and my successors ought to come to the said monastery, at our own expense, as often as a new abbot shall have been made, and there do homage and return to him the power over all the fiefs described above. And when the abbot shall mount his horse I and my heirs, viscounts of Carcassonne, and our successors ought to hold the stirrup for the honor of the dominion of St. Mary of Grasse; and to him and all who come with him, to as many as two hundred beasts, we should make the abbot’s purveyance in the borough of St. Michael of Carcassonne, the first time he enters Carcassonne, with the best fish and meat and with eggs and cheese, honorably according to his will, and pay the expense of shoeing of the horses, and for straw and fodder as the season shall require…

(Feudal Contract of Bernard Atton, Viscount of Carcassonne, 1110 CE)

So if there’s a similar clause as the one bolded above, then the vassal would be obligated to provide those services, but otherwise probably not.